1. Field of the Invention
The present invention relates generally to lighted display cases and more particularly to display cases having light sources that direct light inside the case and toward products, such as might be supported by display case shelves.
2. Related Art
In the past, a variety of shelves have been used inside display cases for the purpose of displaying different items in supermarkets, or other retail establishments. Items for sale are typically placed on the shelves in rows or columns. For example, dairy products in a supermarket may be placed on shelves inside a refrigerated display case with the earlier dated dairy products, which need to be sold first, located near the front and middle of the shelves where the products maybe easily selected by customers. However, problems are encountered in illuminating products arranged in such manner. Products located near the middle of the display shelves are difficult to illuminate when vertical florescent lamps or other lights located near the ends of the shelves are used to light or illuminate the interior of a display case. In such a case, the products located near the lights receive more light or illumination than products located near the front and middle of the shelves. As a result, products near the middle of the shelves are insufficiently illuminated. Additionally, the contrast or uniformity with which the products are illuminated varies significantly from the end of the shelf adjacent the lamp to the middle of the shelf.
When products are positioned on shelving near the light sources in a display case, undesirable glare or excessive bright regions are formed about the products. This localized area of illumination adversely affects the ability to more uniformly illuminate all products at the front of the shelf. Moreover, products located at one part of the shelf may receive more or less attention from a customer than another part of the shelf. Additionally, glare is a source of distraction that diverts the attention of a viewer or consumer away from a displayed product. Attempts to reduce the glare by decreasing the illumination results in even less lighting for the product located near the middle of the shelves. Another common distraction to a consumer or viewer is the heightened contrast or lower uniformity created by the uneven amount of illumination across a display case shelf, when lighting is located near the ends of the shelf. When viewing a series of adjacent display cases, the alternating high and low intensity lighting across the display case shelving is both distracting, and projects an image of non-uniformity. This uneven effect is particularly undesirable when displaying stock of the same product or item across the front of the shelf.
Undesirable glare on the product near the lights may be eliminated by moving or positioning the product or items further towards the rear of the case, away from the immediate area of the light. However, valuable forward display and shelf space is unused by moving product away from the lights. By shifting product in this way, the displayed items would also be located further away from a viewer and appear distant rather than on the shelving up close near the front portion of the displayed case. Similarly, such varied spacing would affect the viewer's perception of the product in the different locations.
With the use of lenses, various of these problems may be reduced or entirely eliminated. Even where they may be reduced, it may be preferable to further reduce such effects, or to achieve even more desirable results with an alternative lighting system. For example,. it may be desirable to further reduce possible glare which may be seen by a viewer or customer outside the display case. Additionally, it may be desirable to selectively distribute light over the shelf as a function of the location along the shelf to be illuminated. Additionally, a fully enclosed light source may improve illumination of product on a shelf with appropriate redirection of light along with improving the performance of the lamp by maintaining the lamp at an optimum operating temperature.